Dural Puncture Epidural Versus Epidural Anesthesia for Cesarean Delivery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Dural Puncture Epidural Versus Epidural Anesthesia for Cesarean Delivery (NCT03915574), a randomized na study. The primary outcome is Onset Time of Surgical Anesthesia.

2. Clinical Question

The primary outcome was onset time of surgical anesthesia, measured in seconds over a timeframe of 2 hours. It was defined from the beginning of injection of the “Induction 1 syringe” to loss of sharp sensation bilaterally at the T6 dermatomal level, assessed with a blunt plastic neurotip. This operational definition makes the endpoint a time-to-criterion measure rather than a general rating of pain relief.

The registry identifies the study as randomized and quadruple masked. Its official title describes it as randomized and double-blind, while the masking field records quadruple masking. The posted record does not explain the difference in those descriptions or specify which roles were masked.

3. Trial Design

This was a randomized, parallel-group study comparing Dural Puncture Epidural with Standard Epidural for cesarean delivery. The registry records quadruple masking and an enrollment of 280. The study is listed as completed, with a start date of 2019-05-09 and a primary completion date of 2022-10-12. The sponsor was the University of Arkansas, and the phase is listed as NA.

The intervention arm received a dural puncture epidural block using a 25 gauge spinal needle, followed by a standard epidural infusion containing 0.062% bupivacaine and 2mcg/ml fentanyl. The comparator description says participants received a standard epidural infusion followed by a standard epidural infusion with the same stated medication concentrations. Further procedural details are not reported in the registry record.

For the primary outcome, the registry reports a median onset time of 422.0 seconds for Dural Puncture Epidural, with an inter-quartile range from 290.0 to 546.0, and a median of 655.0 seconds for Standard Epidural, with an inter-quartile range from 437.0 to 926.0. The reported outcome group sizes are 70.0 and 66.0, respectively. The record does not explain how these outcome group sizes relate to the enrollment field, so they should be read as the group sizes reported for this outcome rather than as a complete account of participant flow.

The registry lists 13 outcome measures and posts a result for one secondary outcome, the number of participants with inadequate neuraxial analgesia or anesthesia. It does not report a sample-size justification, a detailed randomization procedure, allocation concealment, stratification factors, or a prespecified analysis population. These design details are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: 70 mother-infant dyads per arm, Baseline characteristics not collected for infants, Infants were not monitored for adverse events

6. Primary Endpoint

The registry lists the primary outcome as Onset Time of Surgical Anesthesia, measured over 2 hours.

The primary endpoint measures elapsed time from the start of the defined induction injection until sharp sensation is lost on both sides at the T6 dermatomal level. The registry specifies measurement in seconds and a timeframe of 2 hours. Sensation was assessed using a blunt plastic neurotip. Thus, the outcome is tied to a clinical and sensory criterion rather than to an unspecified judgment that anesthesia has taken effect.

The registry reports the endpoint as a median with an inter-quartile range. The median describes the middle of the observed onset-time distribution; the inter-quartile range describes the span from the lower to the upper quartile and gives information about the distribution’s spread. These summaries are useful when time measurements are not well described by a mean and standard deviation, although the registry does not report the reason for choosing this summary or the shape of the underlying data.

A shorter time to the stated sensory criterion corresponds, in general, to reaching that criterion sooner. The endpoint therefore addresses the study’s stated interest in speed of onset. It does not by itself capture every aspect of pain relief, the adequacy of anesthesia throughout surgery, or the use of additional drugs. The registry names those as broader interests, but the primary measure is specifically the time to bilateral loss of sharp sensation at T6. The record does not report a primary-outcome comparison estimate, confidence interval, or p-value.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry presents the primary onset-time result using medians and inter-quartile ranges. A median locates the center of an ordered set of observations: half of the measured values fall at or below it and half at or above it, subject to ties. The inter-quartile range gives the lower and upper quartiles, describing the central spread of the observations. These summaries are often useful for times because observations may be skewed or include unusually long times. That is a general statistical reason for using medians and inter-quartile ranges; the registry does not state the specific rationale used for this trial.

For Dural Puncture Epidural, the median was 422.0 seconds and the inter-quartile range was 290.0 to 546.0. For Standard Epidural, the median was 655.0 seconds and the inter-quartile range was 437.0 to 926.0. These summaries do not provide a confidence interval for the difference between groups. Nor do they indicate whether an analysis compared the full distributions, medians, or another feature of the outcome. A confidence interval, in general, describes uncertainty around an estimated quantity under a statistical model; none for a primary between-group effect is reported in the registry record.

The secondary outcome is binary at the participant level: a participant either was or was not counted as having inadequate neuraxial analgesia or anesthesia during the stated timeframe. The posted counts are 11 among 70.0 in the Dural Puncture Epidural group and 24 among 66.0 in the Standard Epidural group. The registry comparison expresses the difference in risks as -0.206, with an interval from -0.350 to -0.062. A risk difference is the risk in one group minus the risk in the comparison group; here the contrast is oriented from Dural Puncture Epidural relative to Standard Epidural. Its negative sign indicates a lower observed risk in the dural puncture group. The registry does not specify the confidence level for the interval, so no confidence level should be assigned to it.

The record also gives an unadjusted p-value of 0.006 for this secondary comparison. In general, a p-value measures how incompatible the observed data are with a specified null model, under the assumptions of the test. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The registry does not report the test used or its detailed assumptions. Because the p-value is unadjusted, it does not account for testing multiple outcomes unless such an adjustment is described elsewhere; no such adjustment is reported in the registry record.

Other relative-effect summaries are also posted for the secondary outcome: the risk ratio is 0.432, with an interval from 0.230 to 0.811, and the odds ratio is 0.326, with an interval from 0.144 to 0.738. A risk ratio compares the two group risks directly; an odds ratio compares their odds. These measures use different scales and should not be interpreted as interchangeable. The registry does not identify which measure, if any, was the prespecified primary measure for this secondary endpoint.

What do the planning illustrations mean?

The registry includes sample-size planning illustrations based on the observed effect for the secondary endpoint, not on the trial’s own design. The stated assumptions are a two-sided significance level of 0.05, equal allocation, and a normal approximation. For planning for 100% of the observed effect, the illustration gives 70 participants per arm for 80% power and 93 participants per arm for 90% power. For planning for 75% of the observed effect, it gives 133 participants per arm for 80% power and 177 participants per arm for 90% power. For planning for 50% of the observed effect, it gives 315 participants per arm for 80% power and 422 participants per arm for 90% power.

These figures are planning illustrations, not observed power and not evidence about the trial’s original sample-size rationale. They show how required group size changes under the stated assumptions when the target effect is reduced. Smaller effects generally require more information to detect reliably, all else being equal; that is a general statistical principle. The registry does not report that these assumptions were used when the study was designed, nor does it report a design calculation for the primary onset-time outcome.

Why does over-dispersion matter?

Over-dispersion is a general concern when observed variability is greater than a model assumes. If a model underestimates variability, its uncertainty estimates can be too narrow and its tests can appear more decisive than warranted. The registry does not report a model for the primary time outcome, a dispersion assessment, or a count model for the secondary outcome. It is therefore not possible to say whether over-dispersion was assessed or relevant to the sponsor’s analyses.

What remains unclear about the analyses?

The registry records zero analyses and does not post a primary inferential comparison. It does not report the statistical test for the secondary result, the confidence level for the posted intervals, an adjusted analysis, or a plan for handling missing outcomes. The values are therefore best read as posted outcome summaries and an unadjusted secondary comparison, not as a complete account of the trial’s statistical analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 13 outcome measures, but posts results for one secondary outcome in addition to the primary endpoint. It does not report a multiplicity plan, such as a hierarchy for testing outcomes or an adjustment to account for multiple comparisons. The secondary p-value is explicitly unadjusted. When multiple outcomes are examined, unadjusted tests can make chance findings more likely across the collection of tests; this is a general statistical issue. The registry record does not establish how many outcomes were analyzed or whether any adjustment was made outside the posted record.

Missing-data handling is not reported in the registry record. The posted primary outcome group sizes are 70.0 and 66.0, and the secondary outcome uses the same group sizes. The record does not describe participant flow into the outcome analyses, the number with missing measurements, reasons for missingness, or any imputation or sensitivity analyses. The enrollment field is 280, but the relationship between that field and the outcome group sizes is not explained in the posted results. No inference about exclusions, incomplete follow-up, or analysis population can be made from these figures alone.

The registry does not identify whether analyses followed an intention-to-treat approach, a per-protocol approach, or another population definition. It also does not report how protocol deviations were handled. The randomization field establishes the stated allocation method, but it does not by itself establish that every randomized participant was included in every outcome analysis.

The absence of these details limits assessment of the robustness of the reported comparisons. It does not demonstrate that the investigators failed to conduct such analyses; it means their methods and results are not reported in the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

For the Dural Puncture Epidural group, the registry reports zero serious adverse events among 70 participants at risk, zero other adverse events among 70 participants at risk, and zero deaths. For the Standard Epidural group, it reports zero serious adverse events among 66 participants at risk, zero other adverse events among 66 participants at risk, and zero deaths.

These figures describe the events recorded in the registry for the stated groups. They should not be read as proof that no adverse events could occur, or as evidence that the techniques have identical safety profiles. The record does not provide serious adverse event terms, and no top serious-event terms are listed. It also does not describe the collection procedures, event definitions, observation duration beyond the outcome timeframe, or a formal safety comparison. The zero counts are therefore a limited report of recorded events, not a comprehensive estimate of risk.

12. What the Result Does, and Does Not, Mean

The registry’s primary summaries describe the time to a specified sensory criterion in each group. The reported median was 422.0 seconds for Dural Puncture Epidural and 655.0 seconds for Standard Epidural, with the stated inter-quartile ranges. The secondary result reports fewer recorded participants with inadequate neuraxial analgesia or anesthesia in the dural puncture group, alongside an unadjusted risk difference and p-value. These are the posted outcome findings; they do not amount to a full inferential report for the primary endpoint.

The results do not establish the size or precision of a primary between-group effect, because the registry does not report a primary comparison estimate or confidence interval. Descriptive medians can indicate where the middle of each observed distribution lies, but they do not alone quantify uncertainty in a group contrast. The secondary comparison is unadjusted and should be read in light of the absent multiplicity plan and missing analysis details.

The results also do not answer every aim described in the study summary. In particular, a separate result for the percentage of participants who required additional drugs to control pain is not reported in the registry record. The primary endpoint is not a direct measure of all dimensions of pain relief, and the secondary endpoint does not replace an assessment of all surgical anesthesia outcomes.

In general, a randomized comparison is intended to support a fair comparison between assigned groups, but interpretation still depends on the conduct of the trial, outcome completeness, analysis choices, and precision. Details of those elements are not reported in the registry record. These posted statistics should not be taken as medical advice or as a general recommendation about anesthetic technique. They describe the registry results for this study and do not establish how the findings apply beyond the participants and measurements represented in those results.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it puts a time-based endpoint alongside an adequacy outcome. The primary measure has a concrete operational definition: elapsed time from a specified induction event until bilateral loss of sharp sensation at T6. That definition helps clarify what the reported times represent, rather than leaving “onset” as an undefined judgment. The median and inter-quartile range also communicate the center and spread of the recorded times without assuming that the distribution is symmetric.

The record illustrates why descriptive summaries and inferential comparisons serve different purposes. The posted primary summaries allow the reader to compare the reported medians and ranges, but a formal estimate with uncertainty is not reported for that outcome. The secondary result includes an unadjusted comparison, but it relates to a different clinical measure and is accompanied by no reported multiplicity plan. A statistically clear description of each result is not the same as a complete statistical account of the trial.

The registry’s planning illustrations also show how sample-size requirements depend on the effect targeted and the assumptions used. They are explicitly based on the observed secondary effect and are not the original design justification. Keeping planning illustrations separate from observed results helps prevent the mistaken interpretation of a retrospective calculation as proof that a study was adequately powered.

More complete reporting of analysis populations, missing data, the primary comparison, and multiplicity would make it easier to judge precision and robustness. The record therefore offers a useful example of how endpoint definitions, summary measures, unadjusted secondary tests, and reporting completeness all shape interpretation.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

Several limitations specific to this registry record constrain interpretation. Most notably, the primary endpoint is reported with group medians and inter-quartile ranges but without a posted between-group estimate, confidence interval, or p-value. The apparent difference between the displayed medians cannot be treated as a formally tested effect, and no new contrast should be inferred from the summaries alone.

The record gives outcome group sizes of 70.0 and 66.0, while the enrollment field is 280; it does not explain the relationship between these entries. There is no participant flow account, no report of missing outcome data, and no stated analysis population. It is therefore not possible to assess from the registry alone how participants entered the outcome analyses or whether incomplete measurements could affect the results.

The secondary result is unadjusted, and the record does not describe a multiplicity strategy despite listing 13 outcome measures. The statistical test, the confidence level for the intervals, and any adjusted or sensitivity analyses are not reported in the registry record. Only one secondary outcome result is posted, so the stated study interests cannot all be evaluated from the available outcome results.

Some design and conduct details are also absent: the registry does not report the sample-size justification, randomization procedure, allocation concealment, masking roles, protocol deviations, or details of outcome ascertainment beyond the primary endpoint definition. These omissions do not prove that the procedures were absent; they limit what can be verified from the record. The safety figures are zero-count summaries without event terms or fuller collection details, which also limits safety interpretation.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Dural Puncture Epidural Versus Epidural Anesthesia for Cesarean Delivery — NCT03915574.
• Registry record last updated 2023-12-01; status last verified 2023-10.
• Results first posted 2023-12-01.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT03915574 is a completed randomized, parallel-group study sponsored by the University of Arkansas. Its official title is “Dural Puncture Epidural Versus Epidural Anesthesia for Cesarean Delivery: A Randomized, Double-blind Study.” The registry records quadruple masking, an enrollment of 280, a start date of 2019-05-09, and a primary completion date of 2022-10-12. The phase is listed as NA.

The primary outcome was onset time of surgical anesthesia, measured in seconds from the start of the defined induction injection to bilateral loss of sharp sensation at T6, with median and inter-quartile range summaries. A secondary result is posted for participants with inadequate neuraxial analgesia or anesthesia. A formal primary comparison, a multiplicity plan, missing-data methods, and a detailed analysis population are not reported in the registry record.